Urchin-like hierarchical polyaniline (PANI) microspheres were synthesized by a simple template-free method. The morphology and structure of the PANI microspheres were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The results indicated that the microspheres had sez-urchin-like architectures with their surfaces consisting of nanofibers with diameters of about 100 nm and length of 2 mu m. Cyclic voltammetry and galvanostatic charge/discharge measurements in 1M H2SO4 solution revealed that the microspheres had typical electrochemical supercapacitor behavior but showed lower specific capacitance, due to low conductivity or doping level of the PANI microspheres, in comparison with conventional PANI or PANI nanofibers. The effect of experimental parameters on the morphology and electrochemical properties of PANI microspheres is also discussed.